fan question

[star882]

I found a fan with 3 wires(red,black,white).
The back says 12v 0.15a.
Most of the 12vdc fans have 2 wires.
Is the third wire just to make the repairman think the fan is nonstandard?
Is it a 3 phase fan?

 

[lux0]

The 3rd wire is either a tach. pulse output for speed monitoring or a locked rotor indication.

 

[star882]

How do I connect it?

 

[lux0]

"How do I connect it?"

You've indicated in other threads that you are somewhat of an electronics guru, i'm sure you can figure it out.

You connect it to a tach pulse counter or a locked rotor alarm circuit.
Almost every modern motherboard has connections for 3 wire fans.

 

[star882]

What is the function of the 3 wires(red,white,black)?
I want to know how do I use it.

 

[lux0]

The red wire is probably the +ve supply. black is ground and white, as i've said, is either a tach pulse or a locked rotor indicator.

 

[star882]

I connected the fan to 12v and I get streams of pulses on the white wire.

 

[PsycoBob[Q2]]

correct- now try slowing down the fan (like by putting it flat on the desk) and the pulses will slow down, too.

Depending on the fan, it will pulse a certain number of times per rotation, allowing a monotoring program to track it, and do things like- Sound an alarm; shut down the system; Speed up all the other fans; Log it to a file; or some combination of the above.